Jump to content


Recommended Posts

But,we know that in transformers,power is constant. A step-up transformer steps up the voltage and steps down the current to maintain a constant power. (also, step-down transformer steps down voltage and steps up the current).

In this view,current is not directly proportional to the voltage right?

how is it we can apply Ohm's law then?

Link to comment
Share on other sites

You can apply Ohm's law to the primary and the secondary, where each has an inductive load. The transformer doesn't have a voltage drop across the primary to the secondary, so you wouldn't use it there.

Link to comment
Share on other sites

... in transformers,power is constant...


No. Power into primary winding = power out of secondary winding + heat


... current is not directly proportional to the voltage right?...


Yes, it is. More voltage into the primary will result in more primary current and thus more Voltamperes


The transformation is Voltampers

Those Voltamperes available in the secondary can be of low voltage winding capable of some current. The multiplication VxI is still (Voltampers).

If the secondary winding is made of higher voltage, will result in more secondary load current.


The secondary current will increase if the secondary voltage is increased or the secondary resistance load is decreased. UP to a limit. The part you are missing is the limit of the power transformed figure.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.